Surface and charge transport characterization of polyaniline-cellulose acetate composite membranes.
Surface and charge transport characterization of polyaniline-cellulose acetate composite membranes.
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DOI：
10.1021/jp109455m
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发表时间：
2011-02
期刊：
影响因子：
--
通讯作者：
A. Qaiser;M. Hyland;D. Patterson
中科院分区：
文献类型：
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作者：
A. Qaiser;M. Hyland;D. Patterson
本研究阐明了聚苯胺（PANI）复合膜的电荷传输过程，并将其与PANI沉积位点和PANI表面在基底微孔膜上分层的程度相关联。聚苯胺沉积在醋酸纤维素微孔膜的表面层或孔内，使用各种原位化学聚合技术。利用傅里叶变换红外光谱（FTIR）和X射线光电子能谱（XPS）表征了聚苯胺在基膜表面的分层程度及其氧化和掺杂状态。PANI沉积在膜上表现出强烈的依赖于聚合技术和聚合时间内的一个单一的技术。在XPS中，使用复合膜的C 1 s和N 1 s核心水平光谱的去卷积来量化PANI在表面沿着分层的程度及其氧化和掺杂状态。对于所有采用的技术，PANI不完全覆盖基础微孔膜的表面。然而，在特定技术中，分层的程度随着聚合时间而增加。电化学阻抗谱（EIS）研究了电荷通过主体膜的传输和在膜/电极界面的电荷转移。使用等效电路建模技术对数据进行了分析。模型参数表明，聚苯胺沉积在表面增强的界面电荷转移，但该过程依赖于膜的表面覆盖的程度。此外，在本体膜的电荷传输依赖于聚苯胺的嵌入水平，这取决于所采用的聚合技术。此外，还进行了电解质浸泡膜的EIS，以评估在电解质的存在下，聚苯胺沉积位置对电荷传输的影响。PANI分层在孔壁的基膜从在两室电池中的气相聚合表明，电荷传输过程受到强烈的影响，在孔表面的电解质与PANI层的相互作用。这项研究成功地表明，聚苯胺复合膜的电荷传输机制的依赖于聚苯胺沉积网站和在膜表面的表面分层的程度。
This study elucidates the charge transport processes of polyaniline (PANI) composite membranes and correlates them to the PANI deposition site and the extent of PANI surface layering on the base microporous membranes. PANI was deposited either as a surface layer or inside the pores of cellulose acetate microporous membranes using various in situ chemical polymerization techniques. The extent of PANI layering at the surface of the base membrane and its oxidation and doping states were characterized using Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). PANI deposition on the membranes showed a strong dependence on the polymerization technique and polymerization time within a single technique. In XPS, the deconvolution of C 1s and N 1s core-level spectra of the composite membranes was used to quantify the extent of PANI layering at the surface along with its oxidation and doping states. PANI incompletely covered the surface of the base microporous membranes for all the employed techniques. However, the extent of the layering increased with the polymerization time in a particular technique. The charge transport through the bulk membrane and charge transfer at the membrane/electrode interface were studied by electrochemical impedance spectroscopy (EIS). The data were analyzed using the equivalent circuit modeling technique. The modeling parameters revealed that PANI deposition at the surface enhanced the interfacial charge transfer but the process depended on the extent of the surface coverage of the membrane. In addition, the charge transport in the bulk membrane depended on the PANI intercalation level, which varied depending on the polymerization technique employed. In addition, the EIS of electrolyte-soaked membranes was also conducted to evaluate the effects of PANI deposition site on charge transport in the presence of an electrolyte. PANI layering at the pore walls of the base membrane from diaphragmatic polymerization in a two-compartment cell showed that charge transport processes were strongly affected by the interaction of the electrolyte with the PANI layer at the pore surface. This study successfully showed the dependence of charge transport mechanisms of PANI composite membranes on the PANI deposition site and extent of surface layering at the membrane surface.